Thin film transistors (TFRs) offer low temperature coefficient of resistance (TCR) and low mismatch and have many applications. For example, high precision analog circuits (e.g., voltage references, digital to analog converters) may include one or more TFRs because of the low TCR. Due to process variations, the actual resistance of a TFR may deviate from its target resistance. Such a deviation becomes even more susceptible to process variations as the thickness of a TFR reduces. In high precision analog applications where ultra-thin (e.g., less than 100 Å) TFRs are adopted, even a small amount of resistance deviation may cause mismatch issues.